The Science of Safer Cycling
Cycling is a beautiful sport with a scary truth: it sends more people to emergency rooms than any other. Weather, traffic, and terrain present unavoidable risk, but cycling culture has normalized danger while the industry sells speed before safety.
The myth of the upstroke
One major contributing factor to cycling injuries are clipless pedals. For decades cyclists have been told to "pedal in circles", with clipless allowing you to use your "full" pedal stroke. It's a cycling myth that we've found to be repeated as often as it's been disproven. Research tells a simple story: pulling up wastes energy.
After testing hundreds of elite cyclists and finding no upstroke power, Dr. Jeff Broker, advisor to the US Olympic Committee, published research on cycling biomechanics proving that cyclists don't pull up. Korff et al. (2007) built on this research, finding that actively pulling lowers gross efficiency. Most telling, when professionals provided power meter data to Garcia-Lopez et al. (2016), the researchers found the pros didn't generate upstroke; they pushed harder on the downstroke and let their muscles rest in the recovery phase.
The biomechanics of cycling offer a simple explanation. The quadriceps and glutes generate power through extension on the downstroke, while the smaller hip flexors and hamstrings add little on the upstroke and fatigue quickly (Coyle et al., 1991; McDaniel et al., 2013).
You don’t need to think about your pedal stroke to cycle efficiently. Consistent practice, an awareness of your body, and a good bike fit will do more for your efficiency and comfort than gimmicks and gear. We found this video helpful in breaking down the literature.
So, if it’s not the mythical “circular pedal stroke,” then where do the performance gains of clipless pedals come from?
Why cyclists still clip in
Rigid soles, not the upstroke, are what make clipless setups efficient. A review of the foot–shoe–pedal interface found that stiff cycling shoes transferred power more effectively and increased pressure under the medial forefoot compared with sneakers.
The same review reported that sneakers caused higher muscle activity in the quadriceps and hamstrings, while rigid cycling shoes reduced activation during the power phase, allowing riders to produce the same output with less effort. Some experiments even observed lower heart rates when participants used rigid shoes instead of sneakers at high workloads. These findings show that the real benefit of clipless systems lies in a stable, rigid platform that minimizes wasted energy, not in pulling up on the pedals.
Clipless pedals also lock your foot in the correct position and stop it from sliding around, which makes high‑cadence or wet‑weather riding more secure and ensures your hips, knees and ankles stay aligned. You shouldn't have to be locked to your bike to experience these benefits.
Norms evolve
Helmets offer a useful parallel in understanding how cycling safety norms evolve. Cyclists pushed back on UCI attempts to mandate helmet use, citing performance as the drawback. It wasn’t until Kivilev’s death in 2004 that helmet use was mandated in the pro peloton. Today, helmets are an area for performance gains and you will rarely see a road cyclists without one.
For crit racers and velodrome sprinters putting in all-out efforts in short bursts, the risk trade-off can feel justified. For the rest of us, increasing the potential for injury makes little sense, especially during training and for no performance gain.
Our approach
Our pedal system offers the power transfer of a rigid shoe-cleat connection, but eliminates the mechanical lock. The convex cleat engages the matching concave pedal body, automatically centering the foot during the power phase for maximum efficiency. The system also offers float to reduce pressure on the knee and hip, allowing them to track naturally.
At Bythlon, we believe you shouldn’t have to choose between performance and peace of mind. We hope to reduce cycling injuries by bringing safer performance cycling gear to the masses. We harness engineering, design, and biomechanics to empower every cyclist with confidence and joy, not fear.